A dishwasher is an electric home appliance machine that sprays wash water onto objects to be washed in order to remove foreign matter from the objects.
A conventional dishwasher generally includes a tub that defines a washing space, a rack provided in the tub to receive objects to be washed, a spray arm configured to spray wash water to the rack, a sump configured to store wash water, and a pump configured to supply the wash water stored in the sump to the spray arm.
Meanwhile, some examples of the conventional dishwasher are configured to wash objects to be washed using heated wash water (hot water) or to supply steam to objects to be washed in order to wash or sterilize the objects.
In general, a dishwasher using hot water is configured to heat wash water stored in a sump using a heater provided in the sump in order to generate hot water.
In this case, the heater is exposed in the sump with the result that the heater contacts wash water. For this reason, in the conventional dishwasher, it is necessary to control the water level in the sump such that the heater is not exposed in order to prevent the heater from overheating.
In addition, in the conventional dishwasher, heat from the heater is transferred to wash water only when the heater contacts the wash water. As a result, foreign matter is attached to the surface of the heater, whereby the efficiency of heat exchange is reduced. Furthermore, the surface of the heater is prone to corrosion, which also reduces the durability of the heater.
On the other hand, a dishwasher using steam is classified as a dishwasher that generates steam using a heater provided in a sump or a dishwasher that generates steam using an additional steam generator.
The dishwasher that generates steam using the heater provided in the sump has the same problems as the dishwasher that generates hot water using the heater provided in the sump.
Meanwhile, in a case in which the steam generator includes a storage unit configured to store water and a heater provided in the storage unit to heat the water stored in the storage unit, the dishwasher that generates steam using the steam generator also has the same problems as the dishwasher that generates hot water using the heater provided in the sump.